Teaching a Networking Class for Freshmen: Course Design and Lessons Learned

1. Teaching a Networking Class for Freshmen:Course Design and Lessons Learned Yang Wang, Thomas Blum, and Margaret McCoey Department of Math & Computer Science La Salle University Philadelphia, PA, 19141

2. Literature Work and Our Focus Literature Lab design for network classes: Supports multiple classes e.g., [6,7,8,13] Dedicated for particular classes, e.g., [17] First-year students e.g., Forensics class [4] Our Focus: Freshmen CS/IT students Networking class

3. Outline • Background • Challenges • Design • Principles behind Course Design • Feedback/Assessment • Lessons • Future Work

4. Background • LSU: urban, math&cs Dep., CS/IT majors, diverse population, over 42% from underrepresented ethnic groups • Networking Class: coverage in three classes • CSIT 220: Freshmen networking class Our Focus CSIT 220 Data Communication CSIT 321 Client Support CSIT 320 LANs & Network Administration CSIT 422 Information Security

5. Design • Top-Down vs. Bottom-up • Abandon virtualization technology • The importance of introduction and overview Given the time limit, we will briefly touch on each part

6. Challenges • Lack of prior knowledge • Depth and broadness for serving future class • Identify a minimum set of concepts/protocols • Balance of Theory and Practice • Abstract concepts in networking, e.g., layering • Practice should be simple, and interesting (vs. virtualization) One of the most important factors in teaching is “What the learners already know”. --- David Ausubel

7. Introduction • Question-oriented: • Clarify a few major concepts in networking • Selected based on the relevance to students’ daily lives/prior knowledge • Introduction of important concepts at early stage: e.g., IP address

8. Introduction – Layering Analogy Alex (Letter Carrier) Bobby (Letter Carrier) Application Layer Letter Exchange between Kids Alex and Bobby Transport Layer USPS Network Layer USPS Shipping Segments Link Layer

9. Practice: TCP Protocol Design

10. Practice: MAC Protocol Design

11. Application Layer • Coverage of HTTP, FTP, DNS, and SMTP • Labs: simple, free, lightweight, no installation

12. Transport Layer • Coverage of TCP and UDP • Scenario-based (vs. FSM-based) study of TCP • Lab: same principle • TCPView is highly recommended.

13. Scenarios-based Study of TCPAccumulated ACKs

14. Network Layer and Link Layer • Network Layer: • Coverage of IP, subnetting, router architecture, • Switch-based Lab (instead of routers) • Subnet mask matters • Plug-and-play • Introduction of ARP • Link Layer: • Coverage of MAC, ARP, Ethernet, Switch • ARP lab: • Trace analysis of Wireshark captured packets

15. Overview • Glue • Feature Comparison

16. Principles behind Course Design • How to address the limit background of freshmen? • Resort to alternative approaches: scenarios-based vs FSM for TCP study • Adjust the requirement: link-state routing algorithm for algorithm class • Supplement: coverage of binary system and ASCII in the introduction • Keep it simple and interesting: e.g., not chasing cutting edges, keep labs simple • How to address abstract concepts: • Daily analogies: Internet layers • Common Sense Exercises: Protocol Design Practices • How to ensure students are prepared for downstream classes: • Introduction of key concepts in early stage: e.g., IP • Repetition: DHCP at Application, Transport, Network Layers

17. Feedback and Assessment • Course Average: 4.575/5 • 65% of students positively confirmed the value of the class, e.g.: • “Covered a wide range of the subject, while still helping you learn what you needed to.” • “It gives the student an overall understanding of how networking works as well as a basic understanding of how to administrate and manage computer networks.” • “I felt that the class flowed very well. I feel like I have a very good understanding of the course. It was very informative and the content was very relevant.”

18. Lessons • Platform issue of labs: • A large body of students are using Apple MacBook • MAC lab was scheduled too early: • Easily to forget as the Introduction and Link layers have a long time gap • Lab based on Wireshark trace analysis: • Answers can vary and problems can be all kinds, challenge to grade as well • Better just offer a recorded trace for all the students

19. Future Work • Addressing the negative feedback • Alternative approach comparison: e.g., bottom up • Downstream classes

20. Questions? Teaching a Networking Class for Freshmen:Course Design and Lessons Learned Yang Wang, Thomas Blum, and Margaret McCoey {wang,blum,mccoey}@lasalle.edu Thank you!